/* Copyright (C) 2004 - 2006  db4objects Inc.  http://www.db4o.com

This file is part of the db4o open source object database.

db4o is free software; you can redistribute it and/or modify it under
the terms of version 2 of the GNU General Public License as published
by the Free Software Foundation and as clarified by db4objects' GPL 
interpretation policy, available at
http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
Suite 350, San Mateo, CA 94403, USA.

db4o is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. */
using Db4objects.Db4o.Ext;
using Db4objects.Db4o.Foundation;

namespace Db4objects.Db4o.Internal.Handlers
{
    internal class WeakReferenceHandlerQueue
	{
        private List4 list;

        internal void Add(WeakReferenceHandler reference) {
            lock(this){
                list = new List4(list, reference);
            }
        }

        internal void Poll(IExtObjectContainer objectContainer) {
            List4 remove = null;
            lock(this){
                System.Collections.IEnumerator i = new Iterator4Impl(list);
                list = null;
                while(i.MoveNext()){
					WeakReferenceHandler refHandler = (WeakReferenceHandler)i.Current;
                    if(refHandler.IsAlive){
                        list = new List4(list, refHandler);
                    }else{
                        remove = new List4(remove, refHandler.ObjectReference);
                    }
                }
            }
            System.Collections.IEnumerator j = new Iterator4Impl(remove);
            while(j.MoveNext() && (!objectContainer.IsClosed())){
                objectContainer.Purge(j.Current);
            }
        }
    }
}